/*
    This file is part of the substandard lisp implementation of Standard Lisp
    Copyright (C) 2011 Nicky Nickell

    substandard lisp is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

(de pair (u v)
  (cond
    ((and u v) (cons (cons (car u) (car v)) (pair (cdr u) (cdr v))))
    ((or u v) (error 0 "different length lists in pair"))
    (T NIL)))

/*---
name: pair

doc: |
  explaining what pair is / how it is used!

tests: |
  (pair '(a b) '(1 2)) -> ((a . 1) (b . 2))
  (pair '(a b c) '(1 2 3)) -> ((a . 1) (b . 2) (c . 3))
  (pair '(a b c) '(1 2)) -r> different length lists in pair
...*/
